An internal combustion engine designed so that the nozzle chambers of fuel injectors are connected to a common rail through high pressure lines and performing two fuel injections, for example a pilot injection and a succeeding main injection, is known (for example, see Japanese Unexamined Patent Publication (Kokai) No. 2000-18074).
When using such a common rail, however, when fuel injection is performed, the pressure wave generated in a nozzle chamber of a fuel injector at that time propagates through the high pressure line and reaches the common rail. Next, this pressure wave proceeds in the high pressure rail toward the nozzle chamber. This causes violent pulsation of the fuel pressure in the nozzle chamber.
In this conventional internal combustion engine, the main injection is performed after the pilot injection when this violent pulsation of the fuel pressure occurs in the nozzle chamber due to the reflected wave in the common rail. If performing the main injection when the fuel pressure in the nozzle chamber violently pulsates in this way, however, the problem arises that the injection amount of the main injection greatly fluctuates and ends up greatly deviating from the normal amount.